Method and apparatus for converting hydrocarbons



J. c. BLACK IVI-'arch`lv 3U; 193.7. I

METHOD AND APPARATUS FOR CONVERTING HYDRocARBoNs Original Filed Nov. 6, 1922 Patented Mar. 30, 1937 UNITED ASTATES PATENT OFFICE METHOD AND IN APPARATUS ron coNvmrr- G nrnaocmons John C. Black, Los Angeles, Calif., assignor, by

mesne assignments, to Gasoline Products Company, Inc., Wilmington, Del., a corporation of Delaware Application November 6, 1922, Serial No. 599,403

10 Claims.

porization of the hydrocarbons, and this applica-r tion for Letters Patent refers particularly to the method ofl operating and constructing the heating coil in the before mentioned Patent No. 1,426,813.

In the before mentioned patent I describea process wherein` I employ temperatures as high as 1000o F. and pressures as high as 1000 pounds or more per square inch. To withstand these I' excessive temperatures and pressures, `it is essential to construct the heating elements or coils in a very substantial andsafe manner, and furthermore, it is advantageous to so construct the coil that each pipe or tube caribe easily opened for inspection and cleaning without dismantling it. It is also advantageous to be able to construct the coils outside of the furnace andinsert them in the furnace as a complete coil only requiring connection to the balance of the apparatus to make it operative.

I have discovered that the presence of sulphur in the hydrocarbons, either as free sulphur or as sulphur compounds, will readily attack the steel of the tubes when the coil is in operation under the high pressure and high heat employed in the process. To overcome this diillculty, I prefer to use an alloy steel such as nickel steel or chrome nickel steel, or I may use a tube which has been heat-treated with aluminumwherein a thin coating of aluminum iron or aluminum steel alloy is produced which acts ,as a protectivevsurface to the tube and prevents to a great extent the destructive action ofthe sulphur or sulphur compounds.

Tofwithstand the high pressure employed in the process and especially so un'der the high heat employed, I prefer to use a seamless drawn tube in preference to a pipe made by "welding, such as the ordinary butt or lap-welded `pipe of commerce, as I have found that such pipe will not' stand the strains as well as the seamless tubing. However, I do not wish to limit myself in the con; struction of my coils, as either seamless or weld seam pipe may be employed. Y

Referring to the drawing:

Figure 1 is a sectional elevation of the coil placed in the furnace.

Figure 2 is a plan view of the coil.

(ci. 19e-11o) Figure 3 is an end elevation on the linek 3-3 of Figure 2.

Figure 4 is a sectional view of the return connectors and clean-out blocks.

Fig. 5 is a. sectional view of the coil clamps.

Like numbers refer to like parts in the various figures.

lThe furnace I is of brick construction and may have one or more compartments. In the drawing, I is shown as a furnace with three compartments, one for combustion space, one for the main coil 2 and one for the economizer coil 3.

.The furnace is tted with a stack l to carry off the products of combustion; 5 is an oil or gas burner of the ordinary type; 6 is a door to` afford access to the coil 2; 1 are the blocks which form the crossovers from tube to tube and 8 are clamps to hold the coil together; 9 are angle blocks for making connections one part with the other; I are plugs in theangle blocks and coil blocks to allord means for inspection and cleaning the tubes; II is a connecting tube from the outlet of the coil to the digester or carbon catcher described in my Patent No..1,426,813; I2 are the tubes shown in Figures 2 and 4; I3 the threaded connection of the tube and block; Il, I and I6 are the three sections that go to make up the clamp 8 shown in Figure 3. These three sections are shown in cross section in Figure 5, the clamped tubes I2 being indicated in dotted lines.

It will be noted in Figure 1 that the coil 2 is located entirely within the heating zone of the furnace with only the ingress and egress connections out of the heating zonethis I have founddesirable and in some cases necessary to prevent the corrosive action of the sulphur or sulphur compounds in the hydrocarbons being cracked, as I have found by experience that there is athin coating of carbon deposited upon the inside of the tubes which acts as a protective coating thereon and the sulphur present in the hydrocarbons will not attack the steel either in the tubes or the return connectors. `This protective carbon or carbonaceous deposit is only formed in the tubes or return connectors when they are inside the heating zone of the furnace and is due, I believe, to the baking action of the high heat found in the heating zone and to which added feature of theentlre coil acting as a. heat` absorbing element, no portion of which is outside the heating zone.

threaded to receiveV the threaded end of thiel tube. and the other'end of the boredfhole is-.threagled y oils', a metallic lcracking coil substantially resistant Ato the action of sulphur, said metallic coil to receive removable threaded plugs whicli"act"as closures when the coil is in operation, or when removed will afford means for inspecting and cleaning the tubes. l bore hole, preferably the size of the inside diameter of the tubes, and in communicating with the two previously described bore holes,` the axis of the longitudinal bore holes intersects the axes of the two transverse bore holes; the upper end of the longitudinal bore hole is threaded to receive a threaded plug which has the same function as the 1 two previously described plugs.

the point where it makes full communication with the second tube opening, although itv could be drilled through and threaded the same as the other end, but nothing would be gained by this and expense would be incurred.

In place of threading or screwing the tubes into the blocks, they may be welded in, the blocks then being only counterbored to receive the tubes and not threaded.

To hold the coils as a unit, I employ a three piece cast iron or steel clamp, usually three in number to each coil, one near each end and one in the middle; the middle portion of the clamp is grooved out with semi-circular grooves to receive the tubing and so spaced as to give the proper spacing of the tubes: the upper and lower portions of the clamp are also grooved out in a similar manner to the middle portion and have extended ends through which pass bolts to fasten the top, bottom and middle sections together, thus securely fastening the various tubes into a single rigid unit.

I prefer to construct the coil in a symmetrical manner as to spacing of the tubes, that is to say any lower tube is equidistant from the two tubes immediately above it, and viceversa, any upper tube is equidistant from the two tubes immediately below it.

Furthermore, the blocks at one end of the coil are inclined uniformly in one direction or the other and at the opposite end of the coil in the reverse direction. By this expedient, tubes placed parallel with the longitudinal axis of the coilwill connect opposite blocks, and when all the blocks are so connected, the structure so assembled will form a continuous coil of a single passage withy two open ends, one for inlet and the other for outlet connection. This is all clearly shown in the drawing-Figures 2, 3 and 4.

The blocks may be placed vertically instead of inclined, but if this is done, the tubes will not be parallel with the axis of the coil and it might be dlmcult to insert a cleaning tool into the tube, as it would be sprung out of line a distance equal to the spacing between tube centers. For this reason, I prefe'x` the first described method of oonstruction, but I do not wish to belimited to that type, as the'last mentioned construction will be operative.

What I claim as new is:

1. In an apparatus for cracking petroleum oils for the production of lower boiling hydrocarbon oils, a metallic cracking coil substantially resist- Lengthwise with the blocks is a ant to the action of sulphur, said `metallic coil being composed of an iron and chromium alloy, said chromium in the alloy being in such proportions as to substantially prevent the corrosive action of sulphur. g

2. In anmapparatus for cracking petroleum oils foi: the production 'of loweii' boilingfhydrcarbon being composed of an iron chromium nickel alloy, said alloy-being in such constituent proportions as to substantially prevent the corrosive action of sulphur.

3. An apparatus for cracking hydrocarbons comprising a furnace, a cracking coil positioned within said furnace,'said coil being formed of material comprising an alloy of iron and chromium 'substantially resistant to the corrosive action of sulphur andgmeans insaid furnace for supplying products of combustion thereto.

4. An apparatus for cracking hydrocarbons comprising a furnace, a plurality of tubes in said furnace through which the oil to be cracked is passed under pressure, said tubes being formed of the improvement Awhich comprises heating saidA oil to a cracking temperature in a metallic' coil composed of an alloy of chromium and iron, said coil being substantially resistant to the action of sulphur.

6. In the art of converting higher boiling hydrocarbon oil into lower boiling hydrocarbon oil, the improvement which comprises heating said oil to a cracking temperature in a metallic coil composed of an alloy of chromium,I nickel and iron, said coil being substantially resistant to the action of sulphur. I.

7. An apparatus for use in a process wherein:`

hydrocarbon oil isv subjected to cracking conditions which comprises a container adapted to re-.1A ceive hydrocarbon oil undergoing cracking-comi-f posed of an alloy of iron and chromium substantially resistant to the corrosive or sulfurcompounds.

8. An apparatus for use in a process wherein,A s

hydrocarbon oil is subjected to cracking conditions which comprises a container adapted to reaction of sulfur 1 ceive hydrocarbon oil undergoing cracking composed of an alloy of iron, chromium and nickel substantially resistant to the corrosive action `oi sulfur or sulfur compounds.

9. A process of treating hydrocarbon oil which sistant to the corrosive action of sulfur` orsulfur compounds. v

10. A-process of treating hydrocarbonoil which comprises subjecting' hydrocarbon oil to ay tern`v perature sufficiently high to effect crackingthereof whilevin contact witha container composed 'of an alloy of chromium, nickel andl ironsubstantially resistant tothe corrosive action of sulfuror sulfur compounds.

JOHN c. BLACK.` 

